Conventionally, as an interior member of an automotive vehicle having an air bag door portion such as an instrument panel, a door trim, a center pillar and the like, there has been known a structure described in Japanese Patent Application Laid-Open (JP-A) No. 8-192666.
In the instrument panel having the air bag door portion disclosed in the above publication, a main body portion of the instrument panel and the air bag door portion are integrally formed by so-called dual-injection molding (double injection molding) wherein the air bag door portion (an opening portion) is injection molded with a thermoplastic elastomer, after a main body portion of the instrument panel having an opening portion for the air bag door is injection molded with a thermoplastic resin. Further, as a popularly known structure, there is an instrument panel to which an independent air bag door (injection molded with a thermoplastic elastomer) is later attached.
However, in the instrument panel having the air bag door portion mentioned above, in a case wherein the whole of the instrument panel is constructed of the same resin without replacing the resin of the air bag door portion with the resin of the main body portion, on the basis of characteristics of the resin in the main body portion, the rate of elasticity of the resin in the main body portion is 6 to 7 times higher than the rate of elasticity of the resin (TPO) in the air bag door portion, and the tensile strength in the main body portion is 1.5 to 2 times higher than the tensile strength in the air bag door portion; thus, the break force of a portion for expansion formed in the air bag door portion, an H-shaped break portion (a tear portion), for example, becomes higher in a case of the same thickness, so that it is hard for the air bag door portion to expand, and moreover, a hinge portion may break during expansion. If in order to solve this problem, the thickness of the resin in the break portion is made too thin, underfill, oil-can-like-feeling and deformation are generated. Particularly, in a hard resin instrument panel, since unevenness appears in a periphery of the thin portion at an outer appearance side due to weld shrinkage, an undulation and the like, the quality of the appearance of outer is lowered.
Further, in order to achieve a state wherein both a line of the break portion and an outer periphery of the air bag door portion are completely invisible from the outer appearance side (an invisible type), there is a method of making the break portion thick during molding and then cutting the break portion through a later process. However, in this method, it is very difficult to make the line in the break portion invisible while maintaining a predetermined break force. That is, when the thickness of the resin is made thin, the line and the undulation in the break portion are seen from the outer appearance side even in a case wherein a relief groove is provided, so that the quality of the outer appearance can not be maintained, and the thickness of the resin can not be made sufficiently thin.
When it is difficult to expand the door portion due to the increased break force required during expansion at the break portion (tear portion), which is formed at the air bag door portion, and in order to ameliorate this the thickness of the resin in the break portion is made too thin, the thin portion becomes visible from an outer side and so the quality of the exterior appearance deteriorates; this deficiency is also generated with respect to: a break portion of an interior member of an automotive vehicle (vehicle interior member) such as an instrument panel, door trim, center pillar, or the like, wherein the interior member is integrally formed in accordance with dual-injection molding, using different resins for the main body portion of the vehicle interior member and for the air bag portion; and a break portion of a vehicle interior member wherein the vehicle interior member is obtained by integrally assembling the air bag door portion and the main body portion of the instrument panel by means of a locking hook, a screw or the like, after independently molding the air bag door portion and the main body portion of the instrument panel.
As for technologies relating to the present invention, there are: Japanese Patent Application Laid-Open (JP-A) Nos. 3-281457 and 7-179161 in which stress is concentrated at a foaming layer and a skin in a door-integral foaming instrument panel during an initial period of expansion, Japanese Patent Application Laid-Open (JP-A) No. 2-147452 in which a bead is formed along a tear portion in a later attached resin door, Japanese Patent Application Laid-Open (JP-A) No. 5-185898 in which a blade is set at a distal end of a door metal plate insert in a door-integral foaming instrument panel, Japanese Patent Application Laid-Open (JP-A) No. 7-291078 in which a hinge portion is reinforced in a hard instrument panel obtained by integrally molding a door portion and a main body of the instrument panel, Japanese Patent Application Laid-Open (JP-A) No. 8-290749 in which a hinge portion is reinforced in a skin instrument panel obtained by integrally molding a door base member and an instrument panel base member, Japanese Patent Application Laid-Open (JP-A) No. 2-283546 in which a rib applying maximum shearing force to a tear portion of an independent door is integrally formed, Japanese Patent Application Laid-Open (JP-A) No. 2-109848 in which at a can lid, a thin line is formed in a resin layer so as to surround an opened portion and a weld line is set on the thin line, Japanese Patent Application Laid-Open (JP-A) No. 7-291078 in which a reinforcing member is thermally caulked on a reverse face of a door portion in a resin instrument panel and a notch is formed on a tear line of the door portion, and Japanese Patent Application Laid-Open (JP-A) No. 8-20040 in which a different kind of resin is injected by shielding a metal mold cavity by means of a shielding core so as to perform a core-back immediately before the injection is completed.
The present invention has been made taking the above facts into consideration, and an object of the present invention is to obtain an interior member for an automotive vehicle having an air bag door portion in which the quality of the outer appearance is not deteriorated and the break force of a break portion in the air bag door portion can be reduced to a desired value even in a case of molding the air bag door portion and a main body portion of the trim member for the automotive vehicle with the same resin.
A first aspect of the present invention, there is comprises: a tear portion formed in the air bag door portion; and push-up means for pushing up a portion at both sides or one side of the air bag door portion having therebetween a center portion of the tear portion when a bag body of the air bag is expanded.
Accordingly, an impact load from the bag body of the air bag is concentrated at the center portion of the tear portion when the bag body of the air bag is expanded, and the center portion of the tear portion is smoothly broken. As a result, since the tear portion can be easily broken even when the thickness of the tear portion is large, it is possible to devise to reconcile expansion performance and the quality of the outer appearance (making invisible). Further, since the tear portion is broken first, a load at the hinge portion in the air bag door portion can be lightened. Still further, since the air bag door portion can be made of a hard material with high rigidity, an oil-can-like-feeling and deformation can be prevented.
Further, a second aspect of the present invention, comprises: a tear portion formed in the air bag door portion; and a door hinge portion protecting plate disposed below the air bag door portion, protruding toward a side of the tear portion rather than toward a hinge portion of the air bag door portion and having a high break force.
Accordingly, since the door hinge portion protecting plate is provided, the bag body of the air bag is prevented from being directly abutting the hinge portion of the air bag door portion when the air bag body is expanded, so that the hinge portion of the air bag door portion can be prevented from being broken by the bag body of the air bag. Further, since the hinge portion of the air bag door portion can be protected, breakage can be made with relative ease in the tear portion having a low strength.
Still further, a third aspect of the present invention comprises: a resin fluidizing boundary is set at a core back area, which is for forming a tear portion when the air bag door portion is expanded; and a line of the tear portion is not seen from a side of an outer appearance.
Accordingly, the break force in the break portion can be lowered to a desired value due to a reduction of strength caused by the resin fluidizing boundary, by setting the resin fluidizing boundary in the core back area for forming the break portion when the air bag door portion is expanded. Further, since it is not necessary to make the resin thickness of the break portion significantly thin, the line in the break portion can be made in a state of being fully invisible from the side of the outer appearance, so that the quality of the outer appearance can be prevented from being lowered, heat resistance and aging performance is improved, and support and surface rigidity of a whole of the air bag door portion can be also improved.
Furthermore, in a fourth aspect of the present invention, in the first aspect, the push-up means at a position at both sides or one side of the air bag door portion having therebetween a center portion of the tear portion is a protrusion which is integrally provided with the air bag door portion and which protrudes downward.
Accordingly, the impact load from the bag body of the air bag momentarily acts on the portion when the bag body of the air bag is expanded, and breakage is smoothly performed from the center portion of the tear portion. Further, it is possible to devise to reconcile the quality of the outer appearance and expansion performance through a simple structure in which the portion is merely provided in the air bag door portion.
Moreover, in a fifth aspect of the present invention, in the first aspect, the push-up means is disposed at a lower side of the air bag door portion, and is a metal plate providing a protrusion at at least one of an upper surface or a lower surface of a distal end portion that abuts, when the air bag body is expanded, a position at both sides or one side of the air bag door portion having therebetween the center portion of the tear portion.
Accordingly, due to the metal plate, the impact load from the bag body of the air bag acts on the center portion of the tear portion in a concentrated manner when the bag body of the air bag expands, so that breakage is smoothly performed from the center portion of the tear portion. As a result, it is possible to devise to reconcile the quality of the outer appearance and expansion performance. Further, the structure can be applied to a conventional trim member for an automotive vehicle by using the metal plate.
Further, in a sixth aspect of the present invention, in the first aspect, the push-up means is disposed at a lower side of the air bag door portion and is a metal plate providing a narrow protrusion at an upper surface of a distal end portion that abuts, when the air bag body is expanded, a position at both sides or one side of the air bag door portion having therebetween the center portion of the tear portion, when the air bag body is expanded.
Accordingly, due to the protrusion of the metal plate, the impact load from the bag body of the air bag acts on the center portion of the tear portion in a concentrated manner when the bag body of the air bag expands, so that breakage is smoothly performed from the center portion of the tear portion. At this time, the narrow projection is provided on the upper surface of the front end portion of the metal plate, whereby it is possible to reliably break from the center portion of the tear portion even when the upper surface of the bag body of the air bag is of an uneven shape during an initial period of expansion.
Still further, in a seventh aspect of the present invention, in the first aspect, the push-up means is disposed at a lower side of the air bag door portion and is a metal plate providing a distal end portion that abuts, when the air bag body is expanded, a portion at both sides or one side of the air bag door portion having therebetween the center portion of the tear portion when the air bag body is expanded; a hinge portion of the metal plate is off set toward a side of the tear portion rather than toward the hinge portion of the air bag door portion; and with respect to the hinge portion of the metal plate, a tear portion side position has more rigidity than a fixing portion of the metal plate and a hinge portion of the metal plate.
Accordingly, due to the distal end portion of the metal plate the impact load from the bag body of the air bag acts on the center portion of the tear portion in a concentrated manner when the bag body of the air bag expands, so that breakage is smoothly performed from the center portion of the tear portion. As a result, it is possible to devise to reconcile the quality of the outer appearance and expansion performance. Further, since it is possible due to the metal plate to prevent the bag body of the air bag from being directly abutting the hinge portion of the air bag door portion when the bag body of the air bag is expanded, it is possible to prevent breakage of the hinge portion of the air bag door portion due to the bag body of the air bag.
Furthermore, in an eighth aspect of the present invention, in the first aspect, a hinge portion of the air bag door portion is formed as a thin portion having a predetermined thickness across a predetermined longitudinal width and is adjacent to a case mounting portion, and a groove as a bending point is set in the middle of the longitudinal width of the thin portion.
Accordingly, since the bending point can be set apart from the case mounting portion at which the plate thickness suddenly changes, the rate of local expansion (the rate of the extension of the skin layer) due to bending can be reduced. Further, since the groove is formed at the bending point, the surface expansion length of the bending portion can be increased and the actual expansion rate can be made small, so that it is possible to effectively prevent the hinge portion from breakage due to bending when the bag body of the air bag is expanded.
Moreover, in a ninth aspect of the present invention, in the first aspect, the air bag door portion and the main body portion are integrally formed of the same hard resin material, or separately formed.
Accordingly, even in a case wherein the air bag door portion and the main body portion are integrally or separately formed of the same hard resin material, the impact load from the bag body of the air bag is concentrated at the center portion of the tear portion, so that breakage is smoothly performed from the center portion of the tear portion. As a result, since breakage is easily performed even when the thickness of the tear portion is thick, it is possible to reconcile a expansion performance and a quality of an outer appearance (making invisible). Further, since the tear portion is broken first, it is possible to reduce the load on the hinge portion in the air bag door portion. Still further, since the air bag door portion can be constituted of a hard material having a high rigidity, it is possible to prevent an oil-can-like-feeling and deformation.
Further, in a tenth aspect the present invention, in the first aspect, the air bag door portion and the main body portion are integrally formed of the same hard resin material or separately formed, and a surface of these base materials are covered with a skin with a common or separated tear portion with insert molding or attachment molding.
Accordingly, the impact load from the bag body of the air bag is concentrated at the center portion of the tear portion when the bag body of the air bag expands, so that the base member and the skin of the air bag door portion is smoothly broken. As a result, since breakage can be easily performed even when the thickness of the tear portion in the base member of the air bag door portion is made large, it is possible to reconcile expansion performance and restriction of reduction in the quality of the outer appearance (weld shrinkage and an swelling-shaped unevenness). Further, since it is possible to construct with the hard resin material having a high rigidity, it is possible to prevent an oil-can-like-feeling and deformation. Still further, in a case wherein the air bag door portion and the main body portion are integrally formed of the same hard resin material, a complex mold structure is not required in comparison with a dual-injection molding, and a post treatment of the base member is not required.
Still further, in an eleventh aspect of the present invention, in the first aspect, the air bag door portion and the main body portion are integrally formed of the same hard resin material or separately formed, and a foam layer and a skin with a tear portion commonly formed or separately formed are integrally formed on a surface of the base members thereof.
Accordingly, the impact load from the bag body of the air bag is concentrated at the center portion of the tear portion when the bag body of the air bag expands, so that the base member of the air bag door portion, the foamed layer and the skin are smoothly broken. As a result, since it is possible to easily cause breakage even if the thickness of the tear portion in the base member of the air bag door portion is made large, it is possible to reconcile expansion performance and prevention of underfill during molding. Further, since it is possible to construct with the hard resin material having a high rigidity, there is no swelling feeling which easily generates when estimating heat resistance or the like.
Furthermore, in a twelfth aspect of the present invention, in the third aspect, the main body portion and the air bag door portion of the trim member for the automotive vehicle integrally formed or separately formed are formed of the same resin in accordance with an injection molding.
Accordingly, by setting the resin fluidizing boundary at a core back area, which is for forming a tear portion during expansion of the air bag door portion, it is possible to lower the break force in the break force to a desired value, due to strength reduction which depends on the resin fluidizing boundary. Further, since it is not necessary to make the resin thickness of the break portion significantly thin, the line in the break portion can be made in a state of being fully invisible from the side of the outer appearance, the quality of the outer appearance can be prevented from being lowered, heat resistance and aging performance is improved, and support and surface rigidity of a whole of the air bag door portion can be also improved. Still further, in a case wherein the air bag door portion and the main body portion are integrally formed of the same resin, it is not necessary to paint the trim member for the automotive vehicle while separating into two kinds of materials, so that low cost can be achieved.
Moreover, in a thirteenth aspect of the present invention, in the third aspect, a main body portion and the air bag door portion of the trim member for the automotive vehicle has an air bag door portion integrally formed using different resins in accordance with dual-injection molding.
Accordingly, even in the trim member for the automotive vehicle having the air bag door portion integrally formed by the dual-injection molding, by setting the resin fluidizing boundary at the core back area which is for forming the break portion when the air bag door portion is expanded the break force in the break portion can be lowered to a desired value, due to strength reduction which depends on the resin fluidizing boundary. Further, since it is not necessary to make the resin thickness of the break portion significantly thin, the line in the break portion can be made in a state of being fully invisible from the side of the outer appearance, the quality of the outer appearance can be prevented from being lowered, heat resistance and aging performance is improved, and support and surface rigidity of a whole of the air bag door portion can be also improved.
Moreover, in a fourteenth aspect of the present invention, in the third aspect, a main body portion of a base member and the air bag door portion of the trim member for the automotive vehicle, which are integrally formed or separately formed, are formed using the same resin in accordance with injection molding, the base member having an air bag door portion covered by a skin having a tear portion or lacking a tear portion.
Accordingly, even in the trim member for the automotive vehicle having a so-called skin insert and a skin attachment type air bag door portion wherein the base member is covered by the skin having the tear portion or lacking the tear portion, by setting the resin fluidizing boundary at the core back area which is for forming the break portion when the air bag door portion is expanded the break force in the break portion can be lowered to a desired value, due to a strength reduction which depends on the resin fluidizing boundary. Further, since it is not necessary to make the resin thickness of the break portion significantly thin, the quality of the outer appearance transferred to the skin can be prevented from being lowered, heat resistance and aging performance is improved, and support and surface rigidity of a whole of the air bag door portion can be also improved.
Further, in a fifteenth aspect of the present invention, in the third aspect, a main body portion of a base member and the air bag door portion in the trim member for the automotive vehicle, which are integrally formed or separately formed are formed using the same resin in accordance with injection molding, the base member being covered by a skin having a tear portion, and a foam layer being formed between the skin and the base member.
Accordingly, even in the trim member for the automotive vehicle having a so-called integrally foamed type air bag door portion in which the base member is covered by the skin having a tear portion and the foamed layer is formed between the skin and the base member, by setting the resin fluidizing boundary at the core back area which is for forming the break portion when the air bag door portion is expanded the break force in the break portion can be lowered to a desired value, due to strength reduction which depends on the resin fluidizing boundary. Further, since it is not necessary to make the resin thickness of the break portion significantly thin, underfill during formation can be prevented, heat resistance and aging performance is improved, and support and surface rigidity of a whole of the air bag door portion can be also improved.
Further, in a sixteenth aspect of the present invention, in the third aspect, a cavity is separated in the tear portion by bringing a slide core having a distal end formed in a substantially triangular shape into contact with or in the proximity of a fixed mold, and in this state a resin is injected into each of the separated cavities, moving the slide core slightly backward at about the time filling is completed.
Accordingly, the resin fluidizing boundary can be set at the break portion when the air bag door portion is broken by a simple method of separating the cavity of the air bag door portion, injecting the resin into each of the cavities in this state and slightly moving backward the slide core under condition at about the time filling of the resin is completed, by means of the slide core having the distal end formed in a substantially triangular shape. As a result, since current molding equipment can be used, it is possible to manufacture at low cost. Further, since the method is simple, high reliability can be achieved in functional quality and high productivity can also be achieved.
Further, in a seventeenth aspect of the present invention, in the sixteenth aspect, wherein the break strength of the tear portion can be controlled with a combination of a keep pressure and a core back timing at about the time filling is completed and the thickness near the tear portion.
Accordingly, it is possible to easily and accurately control the break strength of the break portion to a desired value with a combination of the keep pressure before and after filling is completed, the core back timing and the thickness near the break portion.
Further, in an eighteenth aspect of the present invention, in the seventeenth aspect, the core back timing is set to after the filling is completed.
When the core back timing is too soon with respect to completion of filling, the resin filled first is fluidized within a space at the side wherein filling is not completed, so that the resin fluidizing boundary is shifted from the breakage expected portion which depends on the slide core. However, in contrast, in accordance with the present invention, since the core back timing is set to after filling is completed, in addition to the contents stated in claim 6, it is possible to prevent the resin fluidizing boundary and the breakage expected portion from shifting the positions thereof.
Further, in a nineteenth aspect of the present invention, in the eighteenth aspect, the keep pressure after the filling is completed is decreased, separating into several stages, and the core back timing is set to after a second stage of the keep pressure.
Accordingly, since the first stage of the keep pressure can be reliably performed by setting the core back timing to after the second stage of the keep pressure, the weight, size and shape of the formed product can be stabilized, so that generation of deficiencies in the product can be reduced.
Further, a twentieth aspect of the present invention comprises: a tear portion formed in the air bag door portion; and push-up means for pushing up a portion at both sides or one side of the air bag door portion having therebetween a center portion of the tear portion when a bag body of the air bag is expanded, wherein a resin fluidizing boundary is set at a core back area for forming the tear portion, and a line of the tear portion can not be seen from a side of an outer appearance.
Accordingly, the impact load from the bag body of the air bag is concentrated at the center portion of the tear portion when the bag body of the air bag is expanded, since the push-up means is provided. Further, since the resin fluidizing boundary is set at the core back area which is for forming the break portion when the air bag door portion is expanded, it is possible to decrease the break force of the break portion to a desired value, due to strength reduction which depends on the resin fluidizing boundary. As a result, it is possible to devise to reconcile expansion performance and the quality of the outer appearance (making invisible).